The development of a new impedimetric biosensor for the detection of HER3, based on self-assembled monolayers (SAMs) of 4-aminothiophenol on gold electrodes, is reported. Anti-HER3 was used as a biorecognition element for the first time in an impedimetric biosensor. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were applied to characterize the immobilization process and to detect HER3. To provide the best biosensor response all experimental parameters were optimized. In addition, Kramers-Kronigs transform was also performed on the immobilization and measurement processes successfully. The biosensor had a linear detection range of 0.4-2.4 pg/mL. The chrono-impedance technique to real time monitor the interaction between HER3 and anti-HER3 is also implemented. The biosensor has exhibited good repeatability and reproducibility. To demonstrate the feasibility of the biosensor in practical analysis, the artificial serum samples were experienced. (C) 2013 Elsevier B.V. All rights reserved.